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- [00:05]
Sony Kassam
I have a memory that stayed with me for almost 30 years. It's the 1990s. I'm three or four years old. My mom has brought me to work at the convenience store she manages. I'm sitting near the register when two people rush through the door. One of them has a gun. And somehow, a few moments later, I'm helping them steal money from the cash register. There's so much I can picture from that moment. The burglar's clothes, the fluorescent lights above the cash register, the way the store looked. But here's what I discovered while making this the more I dug into that memory, the more I fact checked it with someone who was there, the less certain I became that it all happened the way I remember. The story ended up being more complicated, different from what I'd been telling myself for 30 years. And understanding why is the key to understanding memory itself. Today on 1440 explores memory. How it forms, why it fails us, and what it tells us about the way we see the past and even see ourselves. I'm Sony Kassam. Stay with us. Alright, so it's the morning of the robbery. I know it happened. But beyond those few minutes, I have nothing. I can't tell you what I had for breakfast. I don't remember how we got to the store. And I have no idea what I was wearing the entire morning that preceded. One of the most important memories of my childhood has vanished. And that's because our brains don't save everything we experience like a video camera, they select. In fact, they tend to delete a lot.
- [02:04]
Dr. Daniel Schachter
To the extent that you're doing similar things over and over again, that will work against memory for particular experiences.
- [02:12]
Sony Kassam
That's Dr. Daniel Schachter, a Harvard psychologist who has spent his career studying memory. He's the author of the seven Sins of Memory and our guide on this episode. So most of that morning was ordinary. Another trip to the convenience store, another day following my mom around. Nothing about those moments signaled that they would matter years later. And so my brain hit the delete key over and over. Then a man walked in with a gun. Suddenly, everything changed. What had been an unremarkable morning became a potential threat. And when that happens, our memory making processes start paying attention. This is called encoding the moment when an experience begins its journey into a memory. And one of the biggest factors that determines what gets encoded is, is attention. The robbery captured mine. Everything that came before it didn't. That's why things like novelty and emotions matter. Anything that breaks through the routine gives the brain a Reason to hold on. Smell works the same way, too. But getting into memory is only the first step. Once something is encoded, it has to stay there. The next stage is called storage, the process that allows a memory to survive beyond the moment itself. Thirty years later, I can still picture pieces of the robbery. A couple, the cash register, my terrified mom, the feeling that something unusual was happening. Most memories don't last that long, but emotionally intense experiences often do.
- [03:53]
Dr. Daniel Schachter
But we want a memory system that's going to preserve particularly strong memories of experiences that might threaten our survival, so that we remember later on to have avoid that threatening experience.
- [04:06]
Sony Kassam
From an evolutionary perspective, that makes sense. If something threatens your safety, it's probably worth remembering. Evolution, it seems, is much more interested in armed robberies than breakfast. The part of the brain doing most of the selecting is a small, curved structure deep inside your head called the hippocampus. Roughly the size of your thumb, it acts as the brain's archivist, deciding what gets saved. And it has a clear bias. It prioritizes what feels important for survival.
- [04:40]
Dr. Daniel Schachter
In order to encode new information in a way that will persist over time, we typically need to have some involvement of the hippocampus and the medial temporal lobe. Those regions need to be active in order to get the information into memory in a way that it's going to have a chance to remain available for later retrieval. And we think that over time, the hippocampus needs to interact with different parts of the cerebral cortex.
- [05:13]
Sony Kassam
Now, even if a memory survives, there's one final step. Retrieval. That's the process of bringing a memory back into consciousness. And here's what surprised me. Memory isn't stored like a video file waiting to be played back.
- [05:29]
Dr. Daniel Schachter
I think of memory more as a constructive act, an act of construction, where you're piecing together bits and pieces of information, combining it with information from one event, with other things that you know from other parts of your life and from general knowledge.
- [05:47]
Sony Kassam
Which means the robbery I've been carrying around for so long isn't exactly the same memory I formed as a child. It's the result of three decades of remembering, revisiting and rebuilding that experience. And if that's true, then a troubling question. How much of what I remember actually happened? To find out, I called the one other person who was there that day. My mother.
- [06:22]
Narrator/Announcer
Hey.
- [06:23]
Sony's Mother
Hi, honey. How are you?
- [06:24]
Sony Kassam
Hey, mom. How's it going?
- [06:26]
Sony's Mother
Good. Everything's fine.
- [06:27]
Sony Kassam
All right, so I've got a question for you. Can you think back 30 years ago to the robbery that happened to Both of us?
- [06:35]
Sony's Mother
Yes.
- [06:35]
Sony Kassam
Can you tell me what happened? What do you remember?
- [06:39]
Sony's Mother
It was Saturday morning and I opened the store and within a five here's
- [06:45]
Sony Kassam
where things get even more unsettling. Her version of the robbery is entirely different. I needed to understand how that was possible. After all, we were standing in the same store watching the same two people living through the same moments. So how could we walk away with different memories? As I was about to learn, memory isn't just shaped by what happens to us, it's shaped by what matters to us. That's after the break.
- [07:25]
Narrator/Announcer
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- [08:34]
Sony Kassam
Okay, before I talk about my mother's memory, let me tell you the full story of what I remember. I'm sitting in a high chair near the cash register when suddenly a couple rushes in. They're both wearing dark clothes. The woman has dark curly hair tied back in a ponytail. The man is on the floor with my mother. He has a gun. He's telling her to hand over her jewelry. Then the woman comes over to the register. She has a large bag and I'm helping her put coins inside it. I'm not scared, I'm just watching and helping. But when I talked to my mother, everything started falling apart.
- [09:20]
Sony's Mother
It was Saturday morning and I opened the store and within five minutes two people come inside and they said open the register. I opened the register and they took money and then they snatched my gold chain and they punched me and they ran away.
- [09:41]
Sony Kassam
Oh my gosh. On our phone call, she said the man wasn't on the floor.
- [09:46]
Sony's Mother
No, no.
- [09:47]
Sony Kassam
So no one ever pushed you on to the ground?
- [09:49]
Sony's Mother
No, but they punched me.
- [09:52]
Sony Kassam
It was actually the woman who grabbed her. The man was laser focused on the register. He banged it open, he took the cash. He then took my mom's necklace. And then they Ran. And yes, she confirmed I was right there in my highchair.
- [10:09]
Sony's Mother
Yeah, I was scared, and I was shaking. And immediately, I hold you.
- [10:19]
Sony Kassam
So what happened? Part of the answer goes back to encoding. When something frightening happens, your brain doesn't record the whole room. It locks onto whatever feels most threatening. My mother was a parent staring down an armed robbery. I was a young kid trying to understand why my mother suddenly looked terrified. We encoded different things because we were living through different moments. And then there's something else. Remember the hippocampus, the structure that decides what gets saved? At 3 years old, mine was still developing, which means my memory was probably fragile from the moment it formed. It was assembled by a child's brain as it made sense of something it didn't really understand. But that's only part of it, because even if we had encoded the same things, our memories would still have drifted apart. Every time you remember something, outside information can creep in without you knowing it. Things you read, dreamt, or heard about later, over time, they become harder to distinguish from what you actually experienced. That's what Schachter calls misattribution.
- [11:33]
Dr. Daniel Schachter
So misattribution occurs when we remember some aspect of an event correctly, but we get the source or the context wrong. So we might say, hey, I learned this interesting new fact, and it was, you know, my friend Mark who told me that fact. Well, misattribution would occur if, in fact, it was a different friend that told you this interesting fact or you actually heard it on the radio or you picked it up from a Facebook feed. Misattribution errors often show up in cases of mistaken eyewitness identification, where people may think that a face is familiar because an individual is involved in a crime, but actually it's familiar for a different reason.
- [12:16]
Sony Kassam
Every time we've thought about that morning since, we've been sculpting our own version of it without realizing. So remembering didn't just preserve our memories. It deepened the gap between them, which is why eyewitness testimony can be so unreliable. By this point, I thought I understood the problem. My mother and I focused on different things, and over the course of 30 years, we'd filled in different gaps. It wasn't just that we'd encoded different details. It's that memory isn't really one system at all. It's several. Running independently. You can actually lose one completely, and the others will keep plugging away as best they can, coloring your memory accordingly. We know that because of one man in the 1950s, a young man named Henry Molaison underwent Surgery to treat severe epilepsy. Surgeons removed most of his hippocampus, the structure we talked about earlier, the brain's archivist. The seizures got better, but Henry could no longer form new, lasting memories. If you left the room and came back five minutes later, he wouldn't remember meeting you.
- [13:33]
Dr. Daniel Schachter
He had a devastating inability to remember ongoing experiences. And yet, because of the brain, he could exhibit implicit memory of various kinds. He could learn new skills.
- [13:45]
Sony Kassam
Researchers could teach Henry new tasks, like tracing shapes, and he'd gradually improve, but each time he returned the. He had no memory of doing them before. The skill was there, but the memory of learning it was not.
- [14:01]
Dr. Daniel Schachter
What that taught us is that we need in order to encode new information in a way that will persist over time. We typically need to have some involvement of the hippocampus and the medial temporal lobe. And we think that over time, the hippocampus needs to interact with different parts of the cerebral cortex.
- [14:25]
Sony Kassam
What Henry showed is that these aren't just stages of one process. They're separate systems that can be pulled apart. The system that holds skills and habits, the system that holds facts and personal experience. Lose one, and the other keeps running untouched. My mother and I were both running the second system that morning, the one that holds personal experience. Hers was fully formed, locked onto a direct threat to her own life. Mine was three years old, still under construction, and locked onto something else entirely. A threat to my mom. The result was two different memories. By this point, I'd spent a lot of time thinking about whether my memory of the robbery was accurate. Did the man really have a gun? Was he on the floor? Did I actually help put money in the bag? But here's the thing I didn't expect going into this. I thought memory was squarely about the past, but actually, it isn't, at least not entirely.
- [15:40]
Dr. Daniel Schachter
Memory plays a really important role in our ability to think ahead into the future, to imagine future experiences, and to construct plans on the basis of our simulations of upcoming experiences that, in turn, rely on memory. We can take bits and pieces of our past experiences, recombine them in novel ways, and then run simulations of upcoming experiences. And one way we've learned about this is by studies where you put people in the functional MRI scanner, you ask them to remember a past experience or to imagine a future experience. And what we found is that you see many of the same brain regions showing increased activity.
- [16:26]
Sony Kassam
So memory is the model your brain uses to navigate what comes next. And that robbery built a model in me that I've been running ever since without even realizing it, when I walk into a room, I notice the exits, the track, who's near me, how people are moving, and whether something feels off. It's not something I think about consciously. It just happens. That morning at the convenience store became a template for what danger looks like. And when I really sat with it. This is what arose when my mom and I walked down the street. I always positioned myself on the outside, closest to the traffic. When across the street, I sometimes reach for her hand. I never connected that to the robbery before making this episode. But it makes sense. I was 3 years old watching my mother get robbed at gunpoint. And somewhere in the reconstruction of that memory. But stuck wasn't just the danger in the abstract. It was a very concrete sense of her and her safety. And my brain, I think, has been running that model and trying to protect her ever since. So if memory is constantly working on your behalf, often without your knowledge, is there anything you can do to work with it more intentionally? Yes, a few things. First, sleep matters. The brain spends the night replaying and strengthening what it encoded during the day. In some ways, the night after an experience is just as important as the experience itself. And second, retrieval matters.
- [18:09]
Dr. Daniel Schachter
I certainly find that my wife and I have taken a trip on vacation, and it's something that I want to remember. We had a great time. Part of the way that we can keep that memory alive is by talking about it, looking at some of the photos on our phone, trying to retrieve associated information. Those are ways that we can promote memory.
- [18:31]
Sony Kassam
But looking at photos can also subtly change a memory over time. You may remember not just the event, but the version captured by the camera. And it's not just what you do with your memories after the fact. The health of the system itself matters, too. The hippocampus, that small structure doing so much of this work, responds to something as simple as movement.
- [18:54]
Dr. Daniel Schachter
So there's been some interesting studies, well controlled trials that show older individuals who can benefit, for example, from doing a 40 minute walk three times a week, in terms of various physiological measures of hippocampal function, and also some memory measures that are reflective of healthy hippocampal function. So aerobic exercise, although it's not directly rehearsing memories, can contribute to the health of brain structures that contribute to preserving memory.
- [19:29]
Sony Kassam
It's a reminder that memory doesn't just live in the mind. It's connected to the whole body, too. This brought me to one last question for Professor Schacter. How much of who we are is really just the story we remember?
- [19:49]
Dr. Daniel Schachter
Telling ourselves a lot, I think a lot. Because the stories that we tell about ourselves, that's the basis for our interactions with the world. Those stories may not always be accurate, but they form the basis for our plans for the future, our interactions with other people. I think those stories are essential to understanding how people interact with the world.
- [20:21]
Sony Kassam
That might actually be the biggest thing this episode changed for me. I started out trying to figure out whether I remembered a robbery correctly, which version was right, mine or my mother's. And the answer, I think, is that those questions matter less than I thought they did, or I should say, are less interesting. That morning produced one of the hardest scenes my young mind had to process. And it was working furiously to help a frightened child make sense of something that didn't make sense at all. Maybe that's still what it's doing today. When I walk beside my mom or when I scan a room, the real life event, the exact contours of it, the particulars are all lost. And they'll stay lost because that's how the cognitive world works. The concrete experience is just a second. Then the mind begins its long work of creating a parallel universe within us, one that acts as a shield against present danger, a medicine against pain, and a compass to navigate the unpredictable world. We are constantly rebuilding the story of our lives not because we're trying to get the past right, but I think because we're trying to get the future right. Many thanks to Professor Daniel Schachter for joining us in this episode and thanks to all of you for listening to 1440 explores. I'm Sony Kassam. If you enjoyed this episode and would like to help the show grow, please give us a five star rating and drop a comment on Apple, Spotify or wherever you listen. That's the best way to support us. 1440 explores is a production of Rhyme Media for 1440 Media. This episode was produced by Nicolo Minoni and edited by Dan Bobkoff. Our fact checker is Alice Jones and our sound designer is Jay Cowett. The executive producer at Rime is Dan Bobkoff and the executive producers at 1440 are me and Drew Steigerwald. Sam.